It can sometimes be difficult to actuate or control a device, such as a hydraulic actuator for a valve, when the device is located in an area that is not readily accessible. In such cases, one must either employ a system for remotely-actuating/controlling the device, or one must gain access to the device and then operate it manually. Both of these methods can be costly. When manual operation is required, there can also be significant time delays, hazards, or external environmental conditions that limit access.
The above-described problems are commonplace when working with undersea-located devices. For example, undersea oil production control systems employ a number of valves in piping located on, or proximate, the sea floor. Since many of these valves are only actuated occasionally and/or are located where typical methods of remote control are unsatisfactory, operation of the valves is usually achieved manually by a diver or by a Remote-Operated-Vehicle (ROV). It should be noted that the problems associated with manual operation of an undersea-located device are exacerbated when the device is located at any significant depth below the water's surface.
There have been a number of systems devised to enable remote actuation of an undersea-located device. One such system is taught by Silcox in U.S. Pat. No. 4,095,421. In the Silcox patent, a surface-located acoustic transmitter is employed to send signals to a receiver located proximate an undersea-located rotary valve. Upon actuation, the receiver enables a negative-energy power supply to cause the operation of the rotary valve via a multi-valved actuator. This system has a number of limitations that arise due to the power supply and the arrangement of the valves.
Another example of a system for remotely operating an undersea-located device is taught by Carman et al in U.S. Pat. No. 4,805,657. The patent teaches a valve that includes a receiver and a spring-biased mechanism that can be triggered by an explosive bolt. Once the valve is installed in an undersea location, an operator can transmit an acoustic signal to the valve that will cause the detonation of the explosive bolt. Upon detonation, the spring-biased mechanism causes the valve to change from an open to closed, or closed to open position. Since this system only allows a single actuation of the valve, there is no practical method for testing the actuation system after the valve has been installed.